Policy based routing (PBR) can be used to make routing decisions based on policies set, for example, by a network administrator. Typically, a router receiving a data packet can decide to forward the data packet based on the destination address in the data packet. However, PBR may instead direct the data packet to be forwarded based on the source or destination address. PBR may also direct the data packet to be forwarded based on other criteria, such as the size of the data packet or other information available in a data packet header. Existing techniques of PBR can be insufficient in various cases.